TOKYO (Reuters) - Japan has lodged a protest against Russia over the country's decision to declare Sept. 3 a day of victory over "militaristic Japan" - a move it said would fan mutual antagonism, the top government spokesperson said on Monday.

"The passage of this law could not only stir anti-Japanese sentiment among the Russian people, but may also lead to anti-Russian sentiment among the Japanese people," Chief Cabinet Secretary Hirokazu Matsuno told a press conference on Monday, calling Moscow's move "extremely regrettable".

Russia last week renamed the commemoration day of Sept. 3 - the day after Japan's surrender in World War Two - as the Day of Victory over Militaristic Japan, according to Japanese media reports.

(Reporting by Kaori Kaneko and Mariko Katsumura; Editing by Chang-Ran Kim)